Nitrogen inversion and N–O bond rotation processes in di-and tri-substituted hydroxylamines. A dynamic NMR study
The barriers to inversion in several acyclic di- and tri-substituted hydroxylamines are determined by 1H NMR band shape analysis. The barriers range from 49.1 to 66.8 kJ mol–1 and are discussed in terms of a conformational process which involves nitrogen inversion and rotation around the N–O bond. The N–benzyl group with an ortho hydroxy substituent increases the nitrogen inversion barrier by 10 kJ mol–1, which indicates the requirement of breaking of the intramolecular hydrogen bond prior to inversion.